OUTLINE: This is a dose-escalation study. Patients receive LMB-9 immunotoxin IV over 30 minutes on days 1, 3, and 5. Patients with negative neutralizing antibody to LMB-9 immunotoxin with stable or responding disease receive additional courses every 4 weeks in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of LMB-9 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose-limiting toxicity. Once the MTD is determined, an additional cohort of 6 patients may be treated at the MTD. Patients are followed at 1 month and then every 2 months thereafter.